In this paper, a novel algorithm, based on the Teager Energy Operator (TEO) of a sinusoidal waveform, proposed to detect and analyze the voltage disturbances. Most common power quality (PQ) disturbances at the distribution level such as voltage sags, notches, and capacitor switching are presented. These examples provide the basis for further characterization of other power quality events. Magnitudes of transient PQ events are located in the width of the signal. Furthermore, meaningful components of transients are analyzed. The whole method is implemented and tested over a sample representing recorded disturbances. Simulation and experimental results of different PQ disturbances show that the proposed method is fast and robust in detecting voltage disturbances and requires only a few samples to calculate the energy of a signal. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.